So... I carved my wooden guy and started make a mold for slip casting... I made my first (and worst so far) mold of constructional plaster. So my first question? Should I throw away idea of not using some special ceramic plaster which is around 5 times more expensive than constructional one? Is 20 euros for 25 kg bag normal price for it (for example in your countries)?

Is formsil and plastificator really important for slip-casting clay? It is again pretty expensive fun to buy them and some local internet shop said that it's "recommended"...

What kind of glazes you use or I should use? Is there some better and more trustworthy manufacturer for them? Botz? Some glazes does not need firing before glazing... Are them equal to ones which need firing before glaze?

At first I took just some piece of Picea-wood to see how is it feel to have a lathe and chisel in my hand...

Then I glued together four pieces of good wood (I think it's Alnus) for real thing...

...and shaped it round...

...and thought very carefully what kind of curves it needs to have in future...

So now I had that only job in this road where I feel at least a little bit confidence... Drawing part...

After chisel and sandpaper...

Before befouling my Tiki I wanted to try with that old piece of wood how is plaster (constructional one) acting with wood... Well... Almost... Plaster is too weak... but at least it doesn't hurt wooden object...

So I was brave enough to try it with my Kumuhonua... That plaster dries too fast, I had to throw away first half of the moldbox... and mix the new one... and faster... We are talking about seconds!

Next day I poured the second half... and hoped it will be okay...

...but it wasn't.

Now I'm stuck. I guess I have to search my trousers to find my wallet and get a real ceramic plaster...

Did you soap your tiki before you put plaster on?
Deeper cuts in your mold may help you get more detail.
Go to you tube a type in mold making and see what you find.
Or even get a book, ebay has them cheep.
Good luck!!
As I thought LOTS of you tube on mold making/ slip casting ECT....
http://www.youtube.com/watch?v=Vs4OglBxsgQ

Yes, tikiskip, I soaped it well and with extra caution... I've watched little bit of those videos from Youtube, but haven't find any answers for myself. This forum has been much more detailed place for learning with all common mistakes and useful tips...

My Tiki has pretty sharp edges and that's what makes a problem when I'm trying to get it out from plastermold. I must remove it from right direction, otherwise it will break those edges. I believe that the right ceramic plaster would not break so easily and won't petrify so fast and that would be solution I hope, but I have no experiences at all with it and before buying it I'd like to find out differences between those two plasters to make sure if it's the answer for my problems...

3-piece mold may be pretty good idea, but it means that one of the most important places must be cleaned after slip casting... I would not like to have connection on the front part... I guess I'll try to find some ceramic plaster at Monday and hope it will work better... and use a lot of soap... But meanwhile... Today I glued together next four pieces of wood and try to start carving Lono for the next mug after if it happens to happen that one day Kumuhonua comes alive...

Still no plaster for Kumuhonua, searching for it... as much as I have had time...

But meanwhile I started with Lono... Glued pieces of wood, made it round and made a drawing (which came out perfect, hope to not ruin it with chisel)... and now I'm waiting for right feeling before I touch it with anything sharp... I'll add pictures later... after carving or sometime...

And li'l bit for entertainment... I made a picture using Microsoft Paint... for Facebook's timeline heading... Heh-heh...

Now I talked with a guy who knows those things and he said that ceramic plaster is almost the same as usual constructional plaster... and all the ceramics here use usual one because it's so much cheaper... He also suggest to use vinegar in plaster to avoid drying too fast... 1,25 kg plaster powder for 1 l water... Well... What else... I'll keep trying... And I guess I'll try three-piece mold this time like AlohaStation recommended...

Hi Jerka, I have been making molds now for a couple of years. We started with the cheap plaster and found that it didn't hold up. After a few casts the edges started to crumble.

We only buy first grade mold plaster now and even still after 30 casts parts start to break off. You can glue them back in place with wood glue.

The most important lesson to follow is that once you make a mold it is not truly done until it has completely dried out. That takes around 2 weeks in the sun. If the mold feels cool or cold it is not yet dry. We always wait this long before we make the first cast.